I took my car into a local shop to get a tuneup done awhile back. The one rednecky looking guy told me that he did everything ok except for the fuel filter because it was "stuck" on and that he put a bunch of WD40 on it and for me to come back the next day and he'd replace it then. I was already pretty skeptical about this guy and the place in general in dealing with imports.

Anyways - I go back and he replaces it. A week later I start noticing my gas mileage is really starting to suck. I replace my plugs (staying w/ denzo resistor plugs the whole time). And still not getting any gas mileage back. I just calculated my last gas mileage and I'm really starting to get pissed.
Heres my chart:

Gallons Miles MPG
3.5 90 25.71
9.6 227.7 23.72
10.32 258.3 25.03
10.87 235.3 21.65
10.16 236.7 23.30
10.52 206.3 19.61
11.28 217.6 19.29 <-- Latest MPG

9.46 210.27 22.62 <-- Averages


Almost 18 mpg!!! I used to be at 33. I put the car up on jacks and tried to see if
there were any leaks. I found some drips, it was gas. I haven't really looked for the exact source, but my first guess is going to be the fuel lines near the fuel filter. My fuel system is entirely stock - and so is the engine. Winter shouldn't drop my MPG this low. Anybody offer any advice?
I lost the receipt for that place too.

 

Yeah a shop changed my fuel filter one time on my old car and didn't get the fitting fully tight. I just tightened it myself. Check to see if there are any drips coming from the filter. If it's the lower fitting, you'll probably need a flare nut wrench to tighten the fitting. If it's the banjo bolt on top, use a 6-point closed wrench or socket to tighten it.